1. Field of the Invention
The invention relates to an inkjet dispensing apparatus with a multi-channel cartridge, and in particular, the invention relates to an inkjet dispensing apparatus able to detect leakage between channels thereof.
2. Description of the Related Art
Advances in industries employing chemical and biological processes have created a need for devices that accurately and automatically dispense small quantities of liquids containing chemically or biologically active substances for commercial or experimental use. Accuracy and precision in the amount of liquid dispensed is important both from the standpoint of generating a desired reaction and minimizing the amount of material used. An example of a device with an array of reagents disposed thereupon is a biochip.
From the standpoint of reliability, it is important to prevent different reagents from intermixing during dispensing. In view of this, a multi-channel inkjet cartridge has been disclosed, preventing intermixing of different reagents during dispensing.
As well as during dispensing, intermixing of different reagents may occur due to the leakage in the inkjet printhead. For example, the leakage between different reagents may occur between the cartridge and the chip, between the chip and the barrier layer, or between the barrier layer and the nozzle plate. However, there is no leakage detection apparatus and method for an inkjet dispensing apparatus with a multi-channel inkjet cartridge.
U.S. Pat. No. 6,431,678 discloses an ink leakage detection apparatus. Referring to FIGS. 1a–1b, detectors 21 are formed around contact pads 22 such that the leakage of ink onto both the detector 21 and power or control lines 23 causes a voltage to be propagated through the conductive ink to the detector 21. The detector 21 is in turn coupled to the detection circuit which outputs an ink leakage signal upon receipt of a voltage from a power or a control line 24 or other source. Thus, leakage is detected. It is understood that the inkjet print head 20 includes a substrate 25, a barrier layer 26, and a nozzle plate 27.
Although the apparatus disclosed in U.S. Pat. No. 6,431,678 can detect leakage in some inkjet print heads, it is not applicable to an inkjet dispensing apparatus with a multi-channel inkjet cartridge. Specifically, the detection apparatus shown in FIGS. 1a–1b cannot determine which channel is leaking, and cannot detect leakage between the inkjet cartridge and the chip.